Deaths of adults from arteriosclerotic diseases such as coronary diseases and cerebral vessel diseases have been increasing. It is hitherto known that hyperlipidemia is an important risk factor of these diseases. Hyperlipidemia is a condition in which one or both of cholesterol and neutral fats (mainly, triglycerides) among serum lipids increase. Primary hyperlipidemia which predominates hyperlipidemia is classified into 5 types of I to V according to the most received classification of WHO. Types I, IV, and V of primary hyperlipidemia are characterized by an increase in neutral fat level in the serum, and it is considered that neutral fats have greater influences than cholesterol (Beaumont, J.T. et al., Classification of Hyperlipidemia and Hyperlipoproteinemia, Bull WHO, Vol. 43, pp. 891-908 (1970)).
Type I and type V are inclusively called a chylomicronemia syndrome, and their relation to eruptive xanthoma, hepatosplenomegaly, pancreatitis, lipemia retinalis, etc. has been remarked. Further, type IV is a main factor of endogenous hypertriglyceridemia and, according to the report of the research and investigation team (team leader: Professor Tarui Seiichiro) on primary hyperlipidemia specified as a intractable disease by the Ministry of Health and Welfare, Japan (Investigation Report in 1986, p. 17, (1987)), it is present in 44.6% of male patients and 21.5% of female patients suffering from hyperlipidemia in Japan.
Endogenous hypertriglyceridemia has a relatively high incidence and is said to be often accompanied by obesity, diabetes or abnormal sugar tolerance, hyperinsulinemia, insulin resistance, hyperuricemia, etc.
Recently, reports supporting the theory that hypertriglyceridemia is an independent risk factor of diseases of coronary arteries have been increasing (M. Heikki Frick, et al., N. Enql. J. Med., Vol. 317, p. 1237 (1989)).
Thus, neutral fats are now attracting attention as a risky factor in various diseases more than cholesterol.
It is believed that these hypertriglyceridemic conditions are induced to have their onset in association with single gene disorders or genetic predispositions combined with various environmental factors. Therefore, it is an effective method for preventing hypertriglyceridemia to habitually control an increase of neutral fats. More specifically, a neutral fat level can be controlled by avoiding overweighing, overeating or overdrinking, reducing the body weight, using moderation in drinking, controlling a sugar intake, regularly taking exercises, and the like. As a dietetic treatment, it is recommended to take polyenoic fatty acids while limiting a caloric intake.
Known treating agents for hypertriglyceridemia include Clofibrate drugs and nicotinic acid derivatives. In particular, Bezafibrate and Gemfibrozil are known to reduce especially neutral fats (Rogers R.L., et al., Angiology, Vol. 40, No. 4, Pt. 1, pp. 260-269 (1989), etc.).
In addition, various compositions effective to reduce neutral fats through a daily diet have been proposed. For example, a composition for treating hypertriglyceridemia which comprises an egg having a high iodine content as an active ingredient is disclosed in JP-B-1-48248 (corresponding to U.S. Pat. No. 4,394,376). (The term "JP-B" as used herein means an "examined published Japanese patent application".)
On the other hand, although purple laver is known as a highly nutritional food rich in protein, vitamins, and inorganic salts, it has been conventionally taken only as a favorite food or a taste-hitting food. There is no report on the effect of purple laver to reduce a blood neutral fat level.
Purple laver is also known to be effective in reducing cholesterol. For instance, JP-A-58-150515 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") discloses a health food for reducing a cholesterol level in a living body, which is prepared by molding a purple laver powder mixed with a binder into granules, but no suggestion is made therein as to the action of reducing blood neutral fats. That is, as obviously implied by the above-described classification of hyperlipidemia, hypertriglyceridemai is distinguished from hypercholesterinemia. Drugs possessing an action of reducing cholesterol do not always possess an action of reducing neutral fats. For example, Probucol is a drug predominantly serving to reduce cholesterol, while Gemfibrozil is a drug predominantly serving to reduce neutral fats. From these facts, the composition for preventing or treating hypertriglyceridemia according to the present invention is distinguishable from the above-described health foods in range of application.